Partial short circuits in permanently excited electric motors (PMSM) are difficult to detect, and by way of the back induction voltage they may result in very high short-circuit currents and very high heating rates in the region of 1,000 K/s, unless the entire associated winding phase is short-circuited. This problem is relevant in all redundant designed PMSM drives, in which the rotor of a defective motor is to continue rotating. The above are, in particular, internally redundant motors and torque-adding motors on one shaft or on several coupled shafts. Partial short circuits in motors with star point circuitries of the windings are particularly difficult to detect.
Partial short circuits in motors may only inadequately be detected and evaluated by an evaluation of the current measured at the motor terminals of an electric motor, in particular in motors with a star point circuitry of the windings.
In view of the foregoing, it is at least one object to provide for a device and a method for improved determination of motor faults in permanently excited electric motors with a star point topology. In addition, other objects, desirable features, and characteristics will become apparent from the subsequent summary and detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.